The systemic inflammatory response and its impact on iron nutriture in end-stage renal disease

In most chronic disease conditions, the systemic inflammatory response and its mediators play an essential pathogenic role. Protein calorie malnutriti on, a prominent feature of end-stage renal disease (ESRD), also develops, l argely as a consequence of the systemic inflammatory response. ESRD (uremia ), dialysis, systemic metabolic acidosis, and infections activate the syste mic inflammatory response. Elevations in C-reactive protein and depressions of serum albumin below 4 g/dL are found in more than 50% of ESRD patients undergoing dialysis. In many patients receiving dialysis, the impact of thi s acute-phase response on measures of iron metabolism limits the ability to diagnose iron deficiency. Furthermore, there are risks to iron administrat ion, although data linking iron overload to risk of infection in dialysis p atients is suggestive, not definitive. It seems reasonable to hypothesize t hat the greatest risk of iron administration is in patents who are already infected, and the greater risk would be to raise the serum iron level and t ransferrin saturation precipitously. The total-dose infusion method, which provides all iron required to correct deficiency in 1 dose, is more likely to produce side effects and rapidly raise serum iron levels and transferrin saturation. The use of low-dose intravenous iron supplementation (10 to 20 mg per dialysis treatment or 100 mg every second week) avoids iron overtre atment and should reduce adverse events. In ESRD patients receiving dialysi s, the importance of the systemic inflammatory response in the development of protein calorie malnutrition, the impact of the acute-phase response on iron nutriture, and the response to erythropoietin therapy must be consider ed to achieve an understanding of the altered responses to nutritional ther apy in this setting. (C) 1999 by the National Kidney Foundation, Inc.